The world whites out around him at the call of "Grenade!"
There, just a few feet in front of him, the egg-shaped explosive rolls to a halt and Steve is running straight toward it before he realizes he's moved. He dives on top of it, curling into a ball and frantically waving Agent Carter away. She jogs to a halt, staring at him, but keeps her distance. Steve's glad for it.
He's expendable, she's not.
He braces himself, gritting his teeth, and wondering what it feels like to have your insides blown through your outsides.
The explosion never comes.
Steve opens his eyes to stunned silence and the realization that there is no explosion coming. He slowly sits up, coiled in the dirt, and looks around. Carter's face is wondering; she's smiling just the faintest bit at the edges of her lips. The other recruits look nervous and rattled.
"...Is this a test?" He ventures, confused.
It has to be. Why the hell else would someone throw a dummy grenade at a batch of fresh recruits in the middle of exercises? For some kind of sick kicks?
He glances at Colonel Phillips, who looks surprised and grudgingly impressed. The colonel walks away after muttering something to Dr. Erskine. Erskine turns to him and grins.
That's all the answer he gets.